EWN - Introduction to Electromagnetic Waves and the Wave Nature of Light

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Electromagnetic Waves and the Wave of Nature of Light

Introduction

On a clear spring day you may note the blueness of the sky, or the redness of a blooming rose. All things that you can see are made up of the colors of the rainbow. Yet, what the human eye can see is only the smallest fraction of all light that exists in our universe. Think of how bright and amazing our world would look if we could also see the radio waves carrying signals to our car stereos, or the ultraviolet radiation coming down through our atmosphere from the Sun. The electromagnetic spectrum is our tool for organizing all of the light that we can and can't see.

The way that light behaves has fascinated scientists since before the days of Isaac Newton. Our lesson on electromagnetic waves will explore what we can see, what we can't, and what we know about the wave nature of this thing we call light.

Essential Questions

  1. What characteristics of light support the idea that light behaves as a wave?
  2. How do electromagnetic waves transmit energy as opposed to mechanical waves?
  3. How does the electromagnetic spectrum organize electromagnetic waves?
  4. How can principle of superposition be used to analyze the interaction of waves?
  5. How do waves react to being passed through narrow slits?

Key Terms

  1. electromagnetic wave - A wave created by an accelerating charged particle that combines an electric and magnetic wave.
  2. electromagnetic spectrum - Range of all frequencies of electromagnetic waves, broken down into individual bands.
  3. diffraction - The changing of the path of a wave by passing it by the edge of an obstruction.
  4. constructive interference - When the amplitudes of two overlapping waves add to form a larger amplitude wave.
  5. destructive interference - When the amplitudes of two overlapping waves add to form a smaller amplitude wave.
  6. wave in phase - When the relative position of crests and troughs of the wave are in-line.
  7. wave out of phase - When the relative positions of two crests don't line up. Waves have varying degrees of being out of phase from 0 degrees (in phase) to 180 degrees (one crest aligns with the other's trough).
  8. monochromatic - Light of a specific color (frequency).

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